The field of the disclosure relates generally to electrical distribution systems and, more particularly, to an uninterruptible power supply and a method of use thereof.
Many known electrical distribution systems are served by a local utility's electric grid. These distribution systems, when described in terms of their electrical loads, deliver power to components considered critical and others considered non-critical. Non-critical loads can typically handle brief power interruptions of several seconds or more, whereas critical loads cannot. Many known electrical distribution systems utilize a back-up energy source to ensure service to at least the critical loads is maintained in the event power from the grid is lost. Back-up energy sources include, for example, and without limitation, generators, energy storage devices, and renewable sources, such as wind, hydro, and solar systems, for example. A back-up energy source connects to a load through a transfer switch, which is either automatic or manual. During normal operation, under grid power, the transfer switch generally isolates the back-up energy source from the load. The transfer switch connects the back-up energy source to the load when grid power is lost. Automatic transfer switches facilitate this connection and disconnection automatically.
Many known electrical distribution systems also utilize an uninterruptible power supply (UPS) to ensure power to critical loads is not lost. UPS systems facilitate continuous service to critical loads while under grid power, back-up power, and while transitioning there between. In electrical distribution systems using a generator, for example, as the back-up power source, the UPS regulates the power delivered to the critical loads. Such a generator typically has a capacity two or three times higher than the UPS capacity to compensate for irregularities in the power generated by the generator, which may occur, for example, and without limitation, when the load changes. Consequently, conversion losses are incurred within the UPS during conversion of the generated power, and the generator itself generally has misallocated capacity. Additional losses are also incurred during startup of the generator.